JP2016148140A - Dispersion type water storage method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dispersion type water storage method which eliminates the need for a conventional large-scale flood regulating reservoir when a land is newly developed or an old block is readjusted so as to enable effective utilization of a land while facilitating development and readjustment of a block having a prevention effect on such as flooding in the block and road flooding due to torrential rain and the like.SOLUTION: A plurality of temporary water storage porous concrete layers 1 which comprise porous concrete and which can temporarily store rain water falling on the ground surface are installed dispersedly in a development zone or a readjustment zone, and rain water is temporarily stored in the temporary water storage porous concrete layer 1, so that land development or land readjustment is conducted so as to reduce the size of a regulating reservoir 2 installed on the downstream side of drainage of the development zone or the readjustment zone.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a distributed water storage method.

If forests are lost due to housing development, the water retention capacity will decrease, and rainwater will flow directly into drains such as rivers, which may cause flooding due to sudden increases in rivers.
Therefore, in a development plan with a certain area or more, in order to cope with the increase in the amount of rainwater drainage due to development activities, it is necessary to install a flood control pond according to the development regulations of prefectures.
In other words, the size of the flood control pond is calculated based on the amount of rainfall (10-year probability, etc.) assumed by the region. At the beginning of the rain, a fixed amount of water is drained from the lower orifice. Rainwater is stored in the pond.

However, since the flood control pond is unnecessary except during flood control, it cannot be said that the land is being used effectively.
Then, although the proposal which miniaturizes a flood control pond is also made (refer patent document 1), it does not think that the effect is enough.

In addition, when a flood control pond is provided, there are the following problems.
(1) If there is a flood control pond in the city block, it may be dangerous because children may enter and cause an accident.
(2) Maintenance tends to be inadequate and often impairs aesthetics.
(3) Functional deterioration due to aging, or mud accumulation may not be able to be suppressed.
(4) May be a source of pests such as mosquitoes and moths.

In recent years, the frequency of guerrilla heavy rain, which is caused by global warming and the heat island phenomenon, is increasing. However, the flood control ponds are effective in preventing flooding and road flooding in the city block due to guerrilla heavy rain. Absent.
On the other hand, the inside of the flood control pond is paved, and it is usually used as a parking lot or a sports facility. When heavy rain is likely to flood the river, it is also used as a flood control pond. During heavy rains such as heavy rain, the water volume increases at once, and the car that was stopped in the parking lot by the flowing water may not be able to evacuate because it is immersed in the water, and muddy water also flows, so the water is discharged and the parking lot There is a problem that it takes time and money to remove mud accumulated on the surface of sports facilities.

JP-A-6-10323

  In view of the above circumstances, the present invention eliminates the need for a conventional large-scale flood control pond when developing new land or when developing land in an old block, enabling effective use of the land and guerrillas. The purpose is to provide a decentralized water storage method that can easily develop and maintain a block with the effects of preventing flooding and flooding in the block due to heavy rain.

  In order to achieve the above object, the distributed water storage method according to the present invention comprises porous concrete, and a plurality of temporary water storage porous concrete layers that can temporarily store rainwater that has fallen on the ground surface are dispersed in a development section or a maintenance section. The land development or land improvement is carried out so as to reduce the adjustment pond provided on the downstream side of the drainage of the development section or the maintenance section so as to temporarily store the water in the temporary storage porous concrete layer. .

In the present invention, the porous concrete constituting the temporary water-storing porous concrete layer preferably has a porosity of 15% to 35%, more preferably 25 to 30%.
That is, if the porosity is less than 15%, the penetration rate of rainwater is slow, and there is a risk that water will not be sufficiently drained from the surface during heavy rain. On the other hand, when the porosity exceeds 35%, there is a possibility that a problem may occur in the strength of the porous concrete itself, although it is desirable from the viewpoint of water permeability and water storage function.

The aggregate used for the temporary water-retaining porous concrete layer is generally crushed stone, but is not limited to crushed stone, but is crushed and recycled such as waste plastic, waste brick, and waste tile, or wood chip, bamboo chip, root removal. A crushing material etc. can also be used as needed.
In addition, if a recycled material or a waste material is used as an aggregate as described above, it can contribute to environmental conservation. Moreover, when using crushed stone as an aggregate, although it does not specifically limit, No. 5 crushed stone (13-20 mm), No. 6 crushed stone (5-13 mm), and a mixture thereof are mentioned.

In the present invention, the temporary water storage porous concrete layer preferably has a continuous porosity of 20% or more and a water permeability of 0.5 to 10 cm / s.
If the water permeability coefficient is less than 0.5 cm / s, it takes too much time for water to penetrate to the inside, and the temporary water-storing porous concrete layer may not be able to sufficiently exhibit the flood prevention effect.

Temporary storage porous concrete layer is to mix many small diameter aggregates on the upper layer side, reduce the void diameter even if the porosity is the same, and increase the void diameter by increasing the large diameter aggregate on the lower layer side. It doesn't matter.
In other words, as described above, small waste remains on the upper layer side of the temporary water-storing porous concrete layer, so even if clogging or the like occurs, it is only necessary to clean the surface layer part a little, so maintenance is easy. Become.

In the present invention, the porosity and the continuous porosity are obtained from the volume pressure method (Architectural Institute of Japan, Vol. 75, No. 650, p1043-1050, July 2008), JCI (Concrete Engineering Association). It is measured using the volume method described in the proposed standard (Porosity concrete porosity test method (draft)).
The permeability coefficient is measured using the permeability test method described in the above-mentioned JCI standard draft (Porosity concrete permeability test method (draft)).

In the present invention, the term “temporary water storage” refers not only to the case where rainwater that has fallen on the ground surface has permeated into the interior to be temporarily stored, but also rainwater that has permeated into the temporary water storage porous concrete layer communicates with the temporary water storage porous concrete layer. It is discharged gradually (either continuously or intermittently) through drainage pipes and drainage channels installed, or penetrates into the formation through the side walls and bottom surface of the temporary water storage porous concrete layer Including the case of going.
For example, the behavior of rainwater that has entered the inside of the temporary water storage porous concrete layer from the surface layer of the temporary water storage porous concrete layer includes, for example, the following behavior.
(1) Due to the flow gradient or surface tension, the temporary water storage porous concrete layer flows laterally.
(2) Penetration into the stratum and subgrade (soil) adjacent to the temporary water storage porous concrete layer.
By the way, depending on the permeability of the roadbed itself, aggregates with a particle size of 5 to 20 mm are used, and in the temporary storage porous concrete layer with a porosity of 25% to 30%, the penetration rate (penetration rate) into the roadbed is It is good to set to the grade which becomes 10-20% of the water transmission rate of a temporary water storage porous concrete layer.
In addition, in the case of light rain or when the water is intentionally stored inside the porous concrete layer for a long time, all the rainwater that has entered the temporary storage porous concrete layer may permeate the road bed or the formation layer, except for the evaporation. is there.
(3) Temporary water storage It adheres (adsorbs) to the concrete wall surrounding the voids of the porous concrete layer, retains the water without flowing, and then dries.
By the way, using aggregates with a particle size of 5 to 20 mm and a temporary water storage porous concrete layer with a porosity of 25% to 30%, the water retention rate is about several percent, but the average particle size of the aggregate is small, It has been found that when the void diameter is reduced, it becomes 10% or more.

In the present invention, the temporary water storage porous concrete layer may have an upper surface exposed on the ground surface, or may have a water permeable surface layer such as a water permeable asphalt pavement, and communicate with a part of a road side ditch. The rainwater that has entered the lateral groove may flow into the temporary water storage porous concrete layer.
The surface layer having water permeability is not particularly limited. For example, an interlocking block, a resin mortar, a water permeable protective layer, a water permeable asphalt, an artificial turf mat with water permeable holes, a sand layer on a water permeable sheet, and a sand layer The structure etc. which provided the natural turf layer on the top are mentioned.

  The water-permeable protective layer is not particularly limited as long as it can prevent peeling of the aggregate of the temporary water-storing porous concrete layer and can prevent water permeation to the temporary water-storing porous concrete layer. -Based spraying agents (eg, polyester emulsion-based water-based paints, acrylic emulsion-based water-based paints, epoxy resin-based paints, etc.), modified cements (cement, for example, calcium carbonate, silica powder, silica fume and other admixtures, inorganic The surface of the temporary water-retaining porous concrete layer so that the protective layer forming material, such as a mixture of powder), polymer cement, and small particle size aggregate-filled asphalt emulsion does not block the voids in the temporary water-retaining porous concrete layer It is formed by coating.

The protective layer forming material is used to control the viscosity and the viscosity by controlling the amount of solvent as necessary so as not to block the voids of the temporary water-retaining porous concrete layer at the time of application and to form a water-permeable protective layer having a desired thickness. Adjust liquidity. The amount of the solvent can be appropriately determined according to the construction site by performing trial coating at the site.
The protective layer forming material may be adjusted to a desired color by blending a colorant such as a pigment. That is, the road surface can be formed in a desired color to have a high design property.

The water-permeable protective layer extends along the inner wall surface of the gap from the inlet of the temporary reservoir porous concrete layer downward to 1 to 3 cm (preferably 1.5 to 2 cm) in the depth direction of the temporary reservoir porous concrete layer. It is preferable that the thickness is 0.5 to 1.5 mm (preferably 1 mm).
That is, if the water-permeable protective layer is provided as described above, the porosity of the portion provided with the water-permeable protective layer is reduced by about 5%, but when reaching 1 to 3 cm in the depth direction of the temporary water-retaining porous concrete layer. In addition, since only the temporary water-storing porous concrete having a large porosity is formed, the water permeability effect on the road surface can be sufficiently ensured even if a water-permeable protective layer is present.

Although the distributed water storage method of the present invention is not particularly limited, the runoff coefficient of each part of the development section or the maintenance section can be controlled by at least one of the arrangement of the temporary storage porous concrete layer, the layer configuration, and the storage volume.
The layer configuration is not only the difference in the layer configuration in the thickness direction, but also the overall porosity and continuous porosity, the buffer layer and road bed permeability described later, and the difference in the layer configuration in the road horizontal direction. Including.
Moreover, although the said water storage volume is not specifically limited, For example, it can control by the flat area, thickness, porosity, etc. of a temporary water storage porous concrete layer.

In general, it is preferable to provide a non-permeable or hardly permeable water storage wall around the temporary water storage porous concrete layer.
The temporary storage porous concrete layer distributed in the development area or maintenance area may be connected to the adjacent temporary storage porous concrete layer by piping, etc. A drainage pipe may be connected.

The temporary water storage porous concrete layer may be provided so that the water temporarily stored in the temporary water storage porous concrete layer can permeate below the temporary water storage porous concrete layer or in the ground layer adjacent to the temporary water storage porous concrete layer.
In order to prevent rapid infiltration, a buffer layer made of a material having lower water permeability than the temporary water storage porous concrete layer may be provided between the temporary water storage porous concrete layer and the adjacent ground layer.

Although it does not specifically limit as a buffer layer, The cement improvement road bed formed by mixing a cement paste film | membrane and cement with the earth and lump-like is preferable.
For example, when a concrete layer with low water permeability is used as the buffer layer, cracks generated by concrete shrinkage in the concrete layer may affect the porous concrete layer, leading to strength deterioration of the temporary water storage porous concrete layer. There is no problem of cracking of the buffer layer in the paste film or cement improved roadbed.

Incidentally, the cement paste film can be formed by spraying or applying a cement paste kneaded at a water / cement ratio of 60 to 150 (the mass of water is 1.5 times that of cement) on a ground surface such as a roadbed. The cement paste is semi-penetrated into the soil floor.
Since it is a thin layer, the porosity cannot be directly measured, but it is said that there is a microscopic void of about 1 to 3% in a solidified specimen of a normal cement paste having a water cement ratio of 30 to 40%.
The thickness of the cement paste film is usually about 1 mm.

  On the other hand, the cement-improved subgrade can be formed, for example, by mixing soil and cement of the upper layer of the subgrade. The penetration rate can be adjusted.

That is, as described above, providing a low water-permeable buffer layer and allowing the rainwater in the temporary water-storing porous concrete layer to gradually permeate the roadbed and adjacent strata side contributes to the maintenance of groundwater, It also contributes to surrounding greening.
In addition, the thickness and permeability coefficient of the buffer layer are not particularly limited as long as rainwater in the temporary storage porous concrete layer penetrates into the roadbed side and surrounding soil so that it oozes. It is appropriately determined depending on the storage volume and arrangement of the temporary storage porous concrete layer.

In the present invention, as a method of flowing the temporarily stored water from the temporarily stored porous concrete layer to the drainage path, a method of gradually infiltrating into the roadbed and adjacent strata and draining it as groundwater, a temporarily stored porous concrete layer, For example, a method may be used in which an orifice is provided in the drainage pipe connecting the drainage path, and the drainage path is gradually flowed to the drainage path.
Further, a valve may be provided in the drainage pipe, and the amount of drainage may be appropriately adjusted by changing the degree of opening and closing of the valve by this valve operation.

The distributed water storage method of the present invention is not particularly limited, but it is preferable to provide a water level meter for measuring the amount of rainwater stored in the temporary water storage porous concrete layer.
That is, with such a configuration, the amount of rainwater stored in the temporary water storage porous concrete layer can be easily visually recognized by the water level gauge. In a configuration that allows rainwater stored in the temporary storage porous concrete layer to be drained to the appropriate drainage path by adjusting the valve, the degree of opening and closing of the valve can be adjusted while monitoring the level of rainwater stored in the temporary storage porous concrete layer. Can be controlled. That is, in the unlikely event of heavy rain in which the rainwater that has fallen cannot be temporarily stored in the temporarily stored porous concrete layer, it is possible to quickly and efficiently take measures to prevent inundation and flooding.

The cylindrical body used for the water level gauge is formed of a cylindrical body made of a transparent resin embedded in a temporary water-storing porous concrete layer, or a cylindrical body having a plurality of holes formed in the vertical direction of the wall surface. It is preferable.
That is, it is possible to visually recognize the mud sedimentation degree of the temporary water storage porous concrete layer through the wall surface of the cylindrical body or through the hole in the wall surface. In other words, the height of the mud accumulated in the temporary storage porous concrete layer is confirmed, and defects such as clogging of the temporary storage porous concrete layer are detected at an early stage. Can be dealt with in advance.

  Furthermore, it is preferable to provide at least one water level gauge in each dispersed temporary water-storing porous concrete layer. In the case of a temporary water-storing porous concrete layer having a large area, it is preferable to provide it at a plurality of locations. Moreover, in the structure which provided the valve | bulb, since valve adjustment can be performed confirming a water level meter, providing in the vicinity of each valve is preferable.

In the distributed water storage method of the present invention, a sand basin may be provided in the development area or the maintenance area as necessary. The number and position of the sand basins are appropriately determined depending on the topography, the layout of the building, and the like, and may be one place or a plurality of places.
That is, mud water generated during construction can be received once in the sand basin, and mud and sand can be prevented from entering rivers except for mud and sand.

  Then, after completion of the construction, the entire portion or part of the sand basin may be backfilled with porous concrete to form a temporary storage porous concrete layer.

Further, the distributed water storage method of the present invention embeds a hollow body having a larger porosity than the temporary storage porous concrete layer having a wall through which rainwater that has entered the temporary storage porous concrete layer is permeable to the temporary storage porous concrete layer. It is preferable.
That is, by embedding the hollow body, it is possible to increase the water storage capacity with a limit only by the temporary water storage porous concrete layer. For example, even if the porosity of the temporary water storage porous concrete layer is 35% or less, the void volume capable of storing water in the entire layer can be increased to about 50% (or more).

The hollow body is not particularly limited as long as it is provided on the wall surface through which water that has entered the temporarily stored porous concrete layer can pass and can withstand the load applied from the surroundings during use, but is not limited to synthetic materials such as vinyl chloride resin and polyethylene. Examples thereof include a resin-made perforated pipe, a perforated pipe made of a composite material such as FRP, a perforated steel pipe, a perforated fume pipe, a pipe made of a concrete secondary product, and a box culvert.
The number of holes provided in the hollow body is not particularly limited as long as it can ensure the strength that the peripheral wall of the hollow body is not damaged by a load applied from the surroundings, but rainwater from the temporary storage porous concrete layer side to the hollow body is not limited. In consideration of water permeability, it is preferable to provide as much as possible.

Furthermore, a drainage pump may be provided so that water stored in the temporary water storage porous concrete layer and in the hollow body is drained to the drainage path through the hollow body.
That is, since porous concrete has a filter effect, it is difficult for dust and mud to enter the hollow body. Accordingly, clogging of the drainage pump due to dust, mud, etc. is reduced, and maintenance and management of the drainage pump are facilitated.

  Further, the hollow body has a drain pipe connected to the tip thereof, and the end of the drain pipe is arranged so as to communicate with a drainage path (for example, drainage tub, gutter, pipe tub) and provided in the drain pipe. You may enable it to adjust the amount of drainage to a drainage channel with a valve.

  In the distributed water storage method of the present invention, the position where the temporary water storage porous concrete layer is provided is not particularly limited, but for example, sidewalks, buildings, parks, parking lots, precincts, large-scale commercial facilities, public facilities backyards, Examples include the ground, residential roads, building entrances, and roadside sections of ordinary roads.

The distributed water storage method according to the present invention comprises porous concrete, and a plurality of temporary water storage porous concrete layers that can temporarily store rainwater that has fallen on the ground surface are dispersed in a development section or a maintenance section. The land development or land improvement was carried out so that the adjustment pond provided on the downstream side of the drainage of the development zone or the maintenance zone was reduced by temporarily storing the water in the strata.
Therefore, rainwater that has fallen on the ground surface does not flow along the surface as it is, and passes through the temporarily stored porous concrete layer and is temporarily stored or partially drained or penetrates into the formation side. Go.

That is, a large amount of rainwater does not flow toward the downstream side at a time, and the area of the flood control pond provided on the downstream side can be reduced or eliminated.
In addition, since the area of the flood control area that becomes unnecessary after land development and land improvement can be reduced or eliminated, the maintenance cost of the flood control pond can be reduced and the area of the land section that can be effectively used can be increased.

Even if guerrilla heavy rains occur after land development or land improvement, it can be dispersed and temporarily stored in a porous concrete layer in each block provided in the block, flooding in the block or flooding the road Can be prevented.
Moreover, even if it rains suddenly locally such as guerrilla heavy rain, it can be temporarily stored in the porous storage concrete layer and drained to the river etc. Can also be prevented.

1 schematically shows an arrangement of one embodiment of a development area formed by a distributed water storage method according to the present invention. It is a figure explaining the cross-sectional shape of the temporary water storage porous concrete layer used for the distributed water storage method of FIG. 1, and water storage. It is sectional drawing explaining the 1st construction structure of a temporary water storage porous concrete layer. It is sectional drawing explaining the 2nd construction structure of a temporary water storage porous concrete layer. It is sectional drawing explaining the 3rd construction structure of a temporary water storage porous concrete layer. It is sectional drawing explaining the 4th construction structure of a temporary water storage porous concrete layer. It is sectional drawing explaining the 5th construction structure of a temporary water storage porous concrete layer. It is an expanded sectional view of the water level gauge part of FIG. It is sectional drawing explaining the 6th construction structure of a temporary water storage porous concrete layer. It is sectional drawing explaining the 7th construction structure of a temporary water storage porous concrete layer. It is sectional drawing explaining the 8th construction structure of a temporary water storage porous concrete layer. It is sectional drawing explaining the 9th construction structure of a temporary water storage porous concrete layer. It is a top view which illustrates roughly the other construction form of the dispersion | distribution type water storage construction method concerning this invention.

Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof.
FIG. 1 schematically shows an embodiment of a development area formed by the distributed water storage method according to the present invention.

As shown in Fig. 1, this development area A has public land, residential areas, housing complexes, green spaces / parks, business land, commercial land, etc. partitioned by roads. A regulating pond 2 is provided. In addition, this development area A is equipped with a temporary storage porous concrete layer 1 that temporarily stores rainwater that has entered the gap from the ground surface at the position indicated by the dotted line in FIG. 1 and suppresses the flow of rainwater to the flood control pond 2 side. ing. In the figure, arrows indicate the direction of water flow.
That is, as shown in FIG. 2, the temporary water storage porous concrete layer 1 is obtained by solidifying raw concrete containing aggregate and cement, and the void 11 is formed so that the porosity is 25 to 30%. It has.
Then, rainwater enters the gap 11 and can be temporarily stored.

  In the simple calculation, in the case of the temporary storage porous concrete layer 1 with a porosity of 30%, as shown in FIG. 2, when 50 mm of rain (pretty heavy rain) falls for 30 minutes, it is 83 mm from the bottom of the layer. Water is stored up to a height of 100mm (record heavy rain) in 30 minutes when it falls for 30 minutes. Water is stored up to a height of 167mm from the bottom of the bed, and 150mm of rain (record heavy rain) in 30 minutes. When stored, water is stored up to a height of 250 mm from the bottom of the layer.

Incidentally, in a general development plan, in the case of a development plan of less than 50 ha, the flood arrival time is 10 minutes.
Therefore, if the case of Yokkaichi City, Mie Prefecture is applied to the 10-year probability, Cleveland equation represented by I = a / (t ⁿ + b), a = 5164, b = 37.18, n = 0.90, 10 minutes The average rainfall intensity I (mm / h) is about 114 mm.

Therefore, when the area of each part and the runoff coefficient are set as shown in Table 1, the amount of rainwater generated in each part is set to 114 mm as the average rainfall intensity for 10 minutes and the development area of 10 ha, the amount of rainwater = By substituting into the formula of area × 0.114 × runoff coefficient × 1000, it can be estimated.
Table 1 below shows the total amount of rainwater generated in each part determined by trial calculation and the total amount.
In Table 1, the runoff coefficient does not include permeation from the temporary storage porous concrete layer into the ground or the amount of water gradually drained in the portion where the temporary storage porous concrete layer is provided. It takes into account only the water storage volume.

That is, from Table 1, in the conventional land development scheme, when 10 minutes strength was equivalent 114 mm, since the rainfall sum is 10659M ³ in 1 hour, flood control reservoir 2, requires about ³ dimensions 11000m It can be seen that it is.

  On the other hand, each temporary storage porous concrete when the temporary storage porous concrete layer of the area, thickness and porosity set in each part is provided in the position and area shown in Table 2 in the development area of 10 ha. The amount of water temporarily stored in the strata was calculated. Table 2 shows the estimated amount of water stored in each part and the total amount. In Table 2, POC means porous concrete.

As shown in Table 2 above, the total amount of water stored in the temporary water storage porous concrete layer 1 distributed in each part is estimated to be 7560 m ³ .
Thus, by a temporary water storage porous concrete layer 1 in the development area A is provided dispersed as described above, flood control reservoir 2 from 11000m ³ -7560m ³ is found to be sufficient in size of about 3440M ³ .

In other words, if land development is carried out while providing a temporary storage porous concrete layer 1 from the upstream side of the drainage, a flood control pond 2 having a smaller volume of 1/3 or less than the conventional one is provided on the most downstream side of the drainage in the development area A. You just have to keep it.
Of course, if the thickness and area of the porous concrete layer 1 are increased, the flood control pond 2 can be eliminated.

  Next, a construction example of the temporary water storage porous concrete layer used in the distributed water storage method of the present invention will be described with a specific example.

FIG. 3 shows a first construction form of the temporary water storage porous concrete layer.
As shown in FIG. 3, in this construction mode, the temporary water-retaining porous concrete layer 1 is formed in a portion sandwiched or surrounded by a water-retaining wall 3 made of a non-permeable or hardly-permeable curb or a concrete wall. ing.
The temporary water storage porous concrete layer 1 is formed by solidifying an aggregate (5 to 13 mm) with a fine surface layer portion (1 to 3 cm) with cement, and an aggregate (5 to 5 cm) having a lower layer portion (15 to 60 cm) larger than the surface layer portion. 20 mm) is solidified with cement to form a two-layer structure, and the surface layer portion and the lower layer portion each have a porosity of 25 to 30%.

The temporary water storage porous concrete layer 1 is received by the road bed 5 via a buffer layer 4 having a lower water permeability than the temporary water storage porous concrete layer 1.
The buffer layer 4 is made of, for example, a cement paste film or a cement-modified roadbed.
Further, a drain pipe 6 connected to a drainage path (not shown) is provided through the water storage wall 3 slightly below the upper end so as to penetrate therethrough.

As described above, rainwater that has fallen on the temporary water-storing porous concrete layer 1 enters the gap 11 of the temporary water-storing porous concrete layer 1 from the surface of the temporary water-storing porous concrete layer 1.
And since the temporary water storage porous concrete layer 1 is received by the buffer layer 4, the rainwater that has reached the bottom gradually permeates the road bed 5 through the buffer layer 4, but the rainwater exceeds the infiltration amount. When the water flows in, the rainwater exceeding the infiltration amount is temporarily stored in the temporary water storage porous concrete layer 1.
That is, even when a large amount of rain falls suddenly such as guerrilla heavy rain, the rainwater is temporarily stored in the temporary water storage porous concrete layer 1 and the rapid flow into the drainage downstream side can be delayed.

Further, when rainwater at the level of the drainage pipe 6 or more is stored in the temporary water storage porous concrete layer 1, it overflows from the drainage pipe 6 and flows into the drainage path.
Therefore, it is possible to prevent rainwater from overflowing on the temporary water storage porous concrete layer 1 to cause inundation, flooding of the road, and the like.

Further, as shown by a broken line in FIG. 3, a temporary water storage porous concrete layer 1a is provided in a state in which a concave groove 51 is provided in the road floor 5, and a buffer layer 4a is provided along the inner wall surface of the concave groove 51. It doesn't matter.
That is, since the roadbed 5 has the concave groove 51, compared with the case where it is flat, the area which the temporary water storage porous concrete layer 1a and the buffer layer 4a contact can be enlarged, and rainwater to the roadbed 5 side can be increased. The penetration rate can be increased.

Moreover, since it penetrates from the entire surface of the temporary water-storing porous concrete layer 1, rainwater permeates into the temporary water-storing porous concrete layer 1 from a portion where there is no dust, fallen leaves, etc. .
Therefore, as in the prior art, the problem is that the grating lids provided in the gutters and drainage basins are closed with dust, fallen leaves, etc. 7 and inundation and flooding of the road are caused.
A drain valve 6 may be provided with a valve, and the amount of drainage may be adjusted by opening and closing the valve.

FIG. 4 shows a second construction form of the temporary water storage porous concrete layer.
As shown in FIG. 4, in this construction form, a perforated tube 12 as a hollow body is embedded in the temporary water-storing porous concrete layer 1.

  As shown in FIG. 4, this construction form is the first construction even if the temporary water storage porous concrete layer 1 has the same porosity because the perforated pipe 12 is embedded in the temporary water storage porous concrete layer 1. Compared to the form, the amount of rainwater temporarily stored can be increased by the internal volume of the perforated pipe 12.

FIG. 5 shows a third construction form of the temporary water storage porous concrete layer.
As shown in FIG. 5, in this construction mode, a temporary water storage porous concrete layer 110 is provided on the road 100.

The road 100 is provided with a roadway 130 with the central separation zone 120 in between.
In addition, the road 100 is provided with a temporary water storage porous concrete layer 110 having a porosity of 25 to 30% continuously in the entire width direction except for the pavement 131 of the roadway 130.
That is, in the portion of the roadway 130, the thickness of the temporary water storage porous concrete layer 110 is reduced by the thickness of the pavement 131.

The pavement part 131 of the roadway 130 may be a normal asphalt pavement, a concrete pavement, or a permeable asphalt pavement.
Further, the road 100 is provided with a water permeable side groove 140 adjacent to the roadway 130.

The water-permeable side groove 140 is formed by embedding a perforated pipe 13 for a side groove connected to a drainage path (not shown) in the temporary water storage porous concrete layer 110 along the roadway 130.
The upper surface of the water-permeable side groove 140 is formed without a step with respect to the upper surfaces of the roadway 130 and the sidewalk 150.

A perforated pipe 12 is embedded in the portion of the temporary water storage porous concrete layer 110 constituting the sidewalk 150 in order to increase the water storage volume.
In the sidewalk 150 portion, a water permeable surface layer such as an interlocking block may be provided on the temporary water storage porous concrete layer 110.

This construction form is as described above, and rainwater that has fallen on the roadway 130 flows to the water-permeable side groove 140 side, penetrates into the temporary water storage porous concrete layer 110, and is temporarily stored.
In addition, rainwater that has fallen on the sidewalk 150 penetrates into the temporary water storage porous concrete layer 110 immediately below and is temporarily stored.
On the other hand, rainwater that falls between the sidewalk 150 and the roadway 130 or in the planting 160 portion of the median strip 120 penetrates into the temporary storage porous concrete layer 110 below the planting 160 and is temporarily stored.

FIG. 6 shows a cross section of a parking lot portion which is a fourth construction form of the temporary water storage porous concrete layer.
As shown in FIG. 6, the parking lot 200 is formed with a water storage wall 3a at the periphery, and the temporary water storage porous concrete layer 1 is provided inside the water storage wall 3a so as to be received by the buffer layer 4 on the road bed 5. ing.

Although the temporary porous concrete layer 1 is not specifically limited, The thickness is 15-30 cm and the perforated pipe | tube 14 is embed | buried in the intermediate position of an up-down direction.
One end of the perforated pipe 14 is connected to a drain pipe 15 provided through the water storage wall 3a.

When the drainage pipe 15 faces the side groove 210 provided along the water storage wall 3a and the rainwater level in the temporary water storage porous concrete layer 1 becomes higher than the level of the drainage pipe 15, the side pipe 210 Rainwater can be poured inside.
The drain pipe 15 may be provided with a valve or a stopper.
Incidentally, in a parking lot with an area of 370 m ² , if the porosity of the porous concrete layer is 27% and the thickness of the porous concrete layer is 15 cm, water can be stored up to about 15 m ³ .

7 and 8 show a fifth construction form of the temporary water-storing porous concrete layer.
In this construction form, as shown in FIG. 7, a water level gauge 8 is provided in the vicinity of the water storage wall 3 of the temporary water storage porous concrete layer 1.

As shown in FIG. 8, the water level gauge 8 is made of a transparent resin, has a bottomed cylindrical shape with a plurality of water permeable holes 81 drilled in the peripheral wall, and has a hole embedded in the temporary water storage porous concrete layer 1. One end of the tube 17 is open to the peripheral wall.
It is preferable that the water permeable holes 81 are provided in multiple stages in the vertical direction, and two to four holes are provided at the same height position.

Further, a drain pipe 18 is provided through the water storage wall 3.
One end of the drain pipe 18 opens at the peripheral wall of the water level gauge 8 at the same height as the perforated pipe 17, and a gate valve 18 a is provided at a portion penetrating the valve operation pit 19.
In FIG. 8, reference numeral 82 denotes a lid.

This construction form is as described above, and when the gate valve 18a is closed, rainwater is stored in the temporary water storage porous concrete layer 1 and a large amount of rainwater flows into the drainage route at once. There can be no.
When the water level gauge 8 is monitored and the water level of the water level gauge 8 rises and there is a possibility that the rainwater stored in the temporary storage porous concrete layer 1 overflows, the gate valve 18a is opened to temporarily store the rainwater stored. It can be drained quickly to prevent flooding and flooding due to overflow.

In addition, since the water level gauge 8 is transparent and embedded in the porous concrete layer 1, if mud accumulates in the temporary water storage porous concrete layer 1, the height of the mud easily rises over the peripheral wall of the water level gauge 8. Visible.
That is, the deterioration of the temporary storage porous concrete layer 1 due to clogging of mud can be easily confirmed by the water level gauge 8, and the temporary storage of the porous storage concrete layer 1 is systematically carried out. And flooding of roads can be prevented.

FIG. 9 shows a sixth construction form of the temporary water storage porous concrete layer.
In this construction form, as shown in FIG. 9, an impermeable layer 4b is provided at the bottom of the flood control pond 2, and a temporary water storage porous concrete layer 1 is provided on the impermeable layer 4b.

In the temporary water storage porous concrete layer 1, a drainage perforated pipe 12 a and a water storage perforated pipe 12 b are embedded.
The drainage perforated pipe 12a is connected to the drainage path via a drainage pipe 12c provided so as to penetrate the retaining wall 3b.

On the temporary water-storing porous concrete layer 1, an automobile parking space is provided.
That is, a part of the retaining wall 3b of the flood control basin 2 is provided with an automobile approach path (not shown), and an automobile enters the inside of the flood control pond 2 from the automobile entrance path to temporarily store the porous water. It can be parked on the concrete layer 1.

Further, the retaining wall 3b is provided with a drainage lock 33 connected to the drainage path.
It is preferable to provide the drainage lock 33 at such a height that drains rainwater from the drainage lock 33 before a person on the automobile cannot open the door even if the passenger car is immersed in water.

This construction form is as described above, and the bottom of the flood control pond 2 can be effectively used when the flood control pond 2 is not used, as it has an underground water storage performance at a relatively low cost.
Moreover, even when rainwater suddenly flows into the flood control pond 2 due to guerrilla heavy rain or the like, the rainwater first permeates into the temporary water storage porous concrete layer 1. Therefore, evacuation time for people, cars, etc. in the flood control pond 2 can be earned and evacuated safely.

Moreover, even if muddy water flows into the flood control pond 2, the temporary water storage porous concrete layer 1 becomes a filter, and muddy water can be prevented from flowing into the drainage path.
Incidentally, if the area of the temporary storage porous concrete layer 1 is 1000 m ² , the porosity of the temporary storage porous concrete layer 1 is 30%, and the thickness of the temporary storage porous concrete layer 1 is 40 cm, rainwater will flow into the flood control pond 2 If the amount does not exceed 120 m ³ , the upper surface of the temporary water storage porous concrete layer 1 will not overflow.
In addition, it can replace with the said parking lot and can also be used as a sports facility.

FIG. 10 shows a seventh construction form of the temporary water storage porous concrete layer.
As shown in FIG. 10, in this construction mode, a residential land temporary storage porous concrete layer 1 d in which the house h is built on an inclined land and the exterior of each door, the entrance, the public space, etc. are formed of porous concrete, and the house A temporary water storage porous concrete layer 1e constituting the inner road is provided.
In FIG. 10, reference numeral 3d denotes a retaining wall serving as a water storage wall.

The temporary water storage porous concrete layer 1e is not shown in the drawing so that rainwater falling on the upstream side does not flow at a stretch toward the downstream side in the temporary water storage porous concrete layer 1e, but at a predetermined interval along the road gradient direction. Each is provided with a concrete partition wall having a small hole that becomes an orifice.
The partition wall may not be provided over the entire height from the bottom to the top surface of the temporary water storage porous concrete layer 1e.

FIG. 11 shows an eighth construction form of the temporary water storage porous concrete layer.
As shown in FIG. 11, this construction form is such that the surface layer of the backyard 410 and the parking lot 420 of the large-scale store 400 is the temporary water storage porous concrete layer 1, and the backyard 410 and the parking lot 420 are almost entirely. It is the same level.

The temporary water storage porous concrete layer 1 in the parking lot 420 is provided with a water storage portion 1g formed by deeply digging the road bed 5.
The water storage section 1g includes an impermeable wall provided between the water storage section 5 and a perforated pipe 12g.

The perforated pipe 12g of the water storage section 1g is connected to a drainage pump provided in the drainage pump facility, which is not shown, and can be drained to the drainage path by the drainage pump. It can be used for watering the parking lot 420 and lowering the road surface temperature of the parking lot 420 with heat of vaporization.
Moreover, this construction form is as described above, and it is not necessary to provide a flood control pond adjacent to the large-scale store 400.

In addition, since the backyard 410 and the parking lot 420 are almost at the same level as a whole, it can be made barrier-free and water can be eliminated so that it is clean.
Furthermore, due to the filter effect of the temporary water-retaining porous concrete layer 1, there is almost no inflow of dust or fallen leaves into the perforated pipe 12g.
Therefore, the maintenance frequency of the drainage pump can be reduced.

FIG. 12 shows a ninth construction form of the temporary water-storing porous concrete layer.
In this construction mode, as shown in FIG. 12, a ground 500 is basically formed by a ground temporary water-retaining porous concrete layer 1h and an artificial turf mat 510 laid on the ground temporary water-retaining porous concrete layer 1h. Yes.

Although not shown, the artificial turf mat 510 is composed of a mat main body having a water permeable hole and a fine-grain filler filled so as to fill a gap between the turf-like branches and leaves of the mat main body.
The fine-grain filler is not particularly limited as long as it has a part of rainwater that has fallen on the artificial turf mat 510 or water retention capacity, and sand or rubber chips are used.

A stand 600 is provided adjacent to the ground 500. The stand 600 is also made of porous concrete, and the stand 600 and the ground temporary water-stored porous concrete layer 1h are continuous.
This construction structure is as described above, and rainwater that has fallen on the ground 500 enters the ground temporary storage porous concrete layer 1h through the water-permeable holes provided in the mat body of the artificial turf mat 510, Temporarily stored.

Further, the rainwater that has fallen on the stand 600 permeates into the stand 600 because the stand itself is formed of porous concrete, and the permeated rainwater permeates into the temporary ground water porous concrete layer 1h.
In addition, since water can be retained in the fine-grain filler filled so as to fill the gaps in the turf-like branches and leaves of the mat body, the surface temperature of the artificial turf mat 510 can be maintained at a low temperature for a long time by the heat of evaporation of water. The artificial turf mat 510 can be kept in a comfortable environment.
A sand layer is provided between the mat body and the temporary water-retaining porous concrete layer, and the rainwater temporarily stored in the temporary water-retaining porous concrete layer is filled finely through the water-permeable holes of the mat body by the capillary phenomenon of the sand layer. You may enable it to suck up to the material side.

FIG. 13 schematically shows another embodiment of the distributed water storage method according to the present invention.
As shown in FIG. 13, in this construction method, the sedimentation basins P1 to P3 that may be provided at various locations during the construction are gradually reduced toward the completion of the construction, and finally the temporarily stored porous The construction method is the same as that described above except that the concrete layer 1 is provided.
This construction method makes it easy to ensure the storage function (utilization of excavation points) even when the road cannot be stored under the road surface, and can be used in combination with the mud water generation prevention function.

  The present invention is not limited to the above embodiment. For example, in the fifth construction mode, the water level meter is embedded in the temporary water-storing porous concrete layer. It doesn't matter.

A Development area 1, 1a, 1e Temporary storage porous concrete layer 1d Residential temporary storage porous concrete layer 1g Reservoir (temporary storage porous concrete layer)
1h Ground temporary storage porous concrete layer 2 Flood control pond 3, 3a Reservoir wall 3b Retaining wall 3d Retaining wall (reservoir wall)
4, 4a Buffer layer 4b Impervious layer 5 Subgrade 51 Ditch 6 Drain pipe 7 Garbage, fallen leaves, etc. 8 Water level gauge 81 Water permeation hole 82 Lid 12, 14, 17, 12g Perforated pipe 12a Perforated pipe 12b for drainage Water storage Perforated pipes 15, 18, 12c Drain pipe 18a Gate valve 19 Valve operation pit 100 Road 110 Temporary storage porous concrete layer 120 Median strip 130 Roadway 131 Pavement part 140 Permeable side groove 150 Sidewalk 160 Planting 200 Parking lot 210 Side gutter 33 Drainage Xiamen 400 Large-scale store 410 Backyard 420 Parking lot 500 Ground 510 Artificial grass mat 600 Stand (temporary storage porous concrete layer)
h House P1-P3 Sand basin

Claims (10)

  A plurality of temporary water storage porous concrete layers made of porous concrete and capable of temporarily storing rainwater falling on the ground surface are distributed in the development section or maintenance section, and temporarily stored in the temporary water storage porous concrete layer, A decentralized water storage method characterized in that land development or land improvement is performed so as to reduce the adjustment pond provided on the downstream side of the drainage of the development or maintenance area.   Rainwater that has entered a temporary storage porous concrete layer by providing a buffer layer having a water permeability lower than that of the temporary storage porous concrete layer at the interface between at least one temporary storage porous concrete layer and the ground layer including at least the road bed The dispersion type water storage method according to claim 1, wherein the water penetrates into the formation through a buffer layer.   The distributed water storage method according to claim 1 or 2, wherein the runoff coefficient of each part of the development section or the maintenance section is controlled by at least one of the arrangement, layer configuration, and storage capacity of the temporary water storage porous concrete layer.   The water storage wall is provided around the temporary water storage porous concrete layer, and the drain pipe connected to the drainage path is provided so as to penetrate the water storage wall and communicate with the water storage porous concrete layer. Decentralized water storage method.   The distributed water storage method according to claim 4, wherein a valve or an orifice is provided in the drain pipe.   The distributed water storage method according to any one of claims 1 to 5, further comprising a water level meter for measuring the level of water stored in the porous concrete layer.   The dispersion according to claim 6, wherein the water level gauge is formed of a cylindrical body made of a transparent resin embedded in a temporary water-storing porous concrete layer or a cylindrical body having a plurality of holes drilled in the vertical direction of the wall surface. Type water storage method.   8. A sand basin is provided in a part of a development section or a maintenance section, and the sand basin is filled in a state where a temporary water storage porous concrete layer is formed in at least a part of the sand basin after the completion of construction. Decentralized water storage method described in 1.   The distributed water storage method according to claim 1, wherein a porous tube is embedded in the temporary water storage porous concrete layer.   The distributed water storage method according to claim 9, wherein the drain pipe is connected to the perforated pipe.

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